Biliary atresia (BA) is a rapidly progressive perinatal inflammatory disease, resulting in liver failure. Hepatic Ly6CLo non-classical monocytes promote the resolution of perinatal liver inflammation during rhesus rotavirus-mediated (RRV) BA in mice. In this study, we aim to investigate the effects of inflammation on the transcription factor Nr4a1, a known regulator of non-classical monocytes. Nr4a1-GFP reporter mice were injected with PBS for control or RRV within 24 h of delivery to induce perinatal liver inflammation. GFP expression on myeloid immune populations in the liver and bone marrow (BM) was quantified 3 and 14 days after injection using flow cytometry. Statistical significance was determined using a student’s t-test and ANOVA, with a p-value < 0.05 for significance. Our results demonstrate that non-classical monocytes in the neonatal liver exhibit the highest mean fluorescence intensity (MFI) of Nr4a1 (Ly6CLo MFI 6344 vs. neutrophils 3611 p < 0.001; macrophages 2782; p < 0.001; and Ly6CHi classical monocytes 4485; p < 0.0002). During inflammation, hepatic Ly6CLo non-classical monocytes showed a significant increase in Nr4a1 expression intensity from 6344 to 7600 (p = 0.012), while Nr4a1 expression remained unchanged on the other myeloid populations. These findings highlight the potential of using Nr4a1 as a regulator of neonatal hepatic Ly6CLo non-classical monocytes to mitigate perinatal liver inflammation.

Background

Biliary atresia (BA) is a progressive pediatric inflammatory disease of the liver that leads to cirrhosis and necessitates liver transplantation. The rapid progression from liver injury to liver failure in children with BA suggests that factors specific to the perinatal hepatic environment are important for disease propagation. Hematopoietic stem and progenitor cells (HSPCs) reside in the fetal liver and are known to serve as central hubs of inflammation. We hypothesized that HSPCs are critical for the propagation of perinatal liver injury (PLI).

Methods

Newborn BALB/c mice were injected with rhesus rotavirus (RRV) to induce PLI or with PBS as control. Livers were compared using histology and flow cytometry. To determine the effects of HSPCs on PLI, RRV-infected neonatal mice were administered anti-CD47 and anti-CD117 to deplete HSPCs.

Results

PLI significantly increased the number of common myeloid progenitors and the number of CD34⁺ hematopoietic progenitors. Elimination of HSPCs through antibody-mediated myeloablation rescued animals from PLI and significantly increased survival (RRV+isotype control 36.4% vs. RRV+myeloablation 77.8%, Chi-test = 0.003).

Conclusions

HSPCs expand as a result of RRV infection and propagate PLI. Targeting of HSPCs may be useful in preventing and treating neonatal inflammatory diseases of the liver such as BA.

Background

Hepatopancreatobiliary (HPB) Fellowship training in the Americas consists of 3 distinctive routes with variable curricula: Surgical Oncology Fellowship via the Society of Surgical Oncology (SSO), Abdominal Transplant Surgery Fellowship via the American Society of Transplant Surgeons (ASTS), and HPB Fellowship via the Americas Hepato-Pancreato-Biliary Association (AHPBA). Our objective was to establish a pan-American consensus among HPB surgeons, surgical oncologists, abdominal transplant surgeons, and general surgery residency program directors (GSPDs) on a core knowledge curriculum for HPB fellowship, and to identify topics appropriate for general surgery residency and subspecialty beyond HPB fellowship.

Study design

A 3-round modified Delphi process was used. Baseline statements were developed by the Education and Training Committee of the AHPBA, in collaboration with representatives of the SSO, ASTS, and GSPDs. The expert panel, consisting of members of the 3 societies together with GSPDs, rated the statements on a 5-point Likert scale and suggested editing or adding new statements. A statement was included in the final curriculum when Cronbach's alpha value was ≥ 0.8 and ≥ 80% of the panel agreed on inclusion.

Results

The response rate was 100% for the first round, and 98% for the second and third rounds. Eighty-nine of 138 proposed statements were included in the final HPB fellowship curriculum. Curricula for general surgery residency and subspecialty beyond HPB fellowship included 50 and 29 statements, respectively.

Conclusions

A multinational consensus on core knowledge for an HPB fellowship curriculum was achieved via the modified Delphi method. This core curriculum may be used to standardize HPB fellowship training across different pathways in the Americas.

Limited contemporary data has compared similarities and differences between total laparoscopic (LDP), hand-assisted (HALDP), and open distal pancreatectomy (ODP). This study aimed to examine similarities and differences in outcomes between these three approaches in a contemporary cohort. Methods: Patients undergoing elective LDP, HALDP, and ODP in the NSQIP dataset (2014−2019) were included. Descriptive statistics and multivariate regression analyses were employed to compare postoperative outcomes. Results: Among 5636 patients, 33.9% underwent LDP, 13.1% HALDP, and 52.9% ODP. Compared with the LDP approach, surgical site infections were more frequent in HALDP and ODP approaches (1.2% vs. 2.6% vs. 2.8%, respectively, p < 0.01). After adjustment, the LDP approach was associated with a significantly lower likelihood of surgical site infection (OR 0.25, p = 0.03) when compared to ODP. There was no difference in the likelihood of surgical site infection when HALDP was compared to ODP (OR 0.59, p = 0.40). Unadjusted operative times were similar between approaches (LDP = 192 min, HALDP = 193 min, ODP = 191 min, p = 0.59). After adjustment, the LDP approach had a longer operative time (+10.3 min, p = 0.04) compared to ODP. There was no difference in the adjusted operative time between HALDP and ODP approaches (+5.4 min, p = 0.80). Conclusions: Compared to ODP, LDP was associated with improved surgical site infection rates and slightly longer operative times. There was no difference in surgical site infection rates between ODP and HALDP. Surgeon comfort and experience should decide the operative approach, but it is important to discuss the differences between these approaches with patients.

The hidden curriculum of unspoken professional expectations negatively impacts medical student interest in surgery. Medical student mentorship and early surgical exposure have been shown to demystify the hidden curriculum. Although residents and faculty play a vital role, near-peer mentorship may aid in uncovering the hidden curriculum and promoting medical student interest in surgery, especially for those learners who are underrepresented in medicine. We developed and implemented a formalized near-peer mentorship program composed of quarterly small group Surgical Peer Teacher led lessons and one-on-one Surgical Support Team mentorship meetings covering surgical curriculum topics for medical students at an academic medical school. This structured near-peer mentorship model provides a mechanism to demystify surgical culture, increase early access to surgical mentorship, and develop mentorship skills amongst students. This program aims to uncover the surgical hidden curriculum to improve surgical career support and interest among medical students with less exposure and access to physician role models. This longitudinal mentorship model is student-run and can be easily adapted to enhance existing support models at medical schools. Future studies will evaluate utilization, impact on surgical specialty interest, and efficacy in demystifying the surgical hidden curriculum.

Background

Guidelines recommend limiting minimally invasive pancreaticoduodenectomy (MIPD) to high-volume centers. However, the definition of high-volume care remains unclear. We aimed to objectively define a minimum number of MIPD performed annually per hospital associated with improved outcomes in a contemporary patient cohort.

Patients and methods

Resectable pancreatic adenocarcinoma patients undergoing MIPD were included from the National Cancer Database (2010-2017). Multivariable modeling with restricted cubic splines was employed to identify an MIPD annual hospital volume threshold associated with lower 90-day mortality. Outcomes were compared between patients treated at low-volume (≤ model-identified cutoff) and high-volume (> cutoff) centers.

Results

Among 3079 patients, 141 (5%) died within 90 days. Median hospital volume was 6 (range 1-73) cases/year. After adjustment, increasing hospital volume was associated with decreasing 90-day mortality for up to 19 (95% CI 16-25) cases/year, indicating a threshold of 20 cases/year. Most cases (82%) were done at low-volume (< 20 cases/year) centers. With adjustment, MIPD at low-volume centers was associated with increased 90-day mortality (OR 2.7; p = 0.002). Length of stay, positive surgical margins, 30-day readmission, and overall survival were similar. On analysis of the most recent two years (n = 1031), patients at low-volume centers (78.2%) were younger and had less advanced tumors but had longer length of stay (8 versus 7 days; p < 0.001) and increased 90-day mortality (7% versus 2%; p = 0.009).

Conclusions

The cutpoint analysis identified a threshold of at least 20 MIPD cases/year associated with lower postoperative mortality. This threshold should inform national guidelines and institution-level protocols aimed at facilitating the safe implementation of this complex procedure.